what are some of the differences between them i know the ls1 is faster but what makes it faster?

 

LS1 is an aluminum block. LT1 is Iron. Aluminum = faster.

 

aluminum = lighter = faster

 

ls1 heads flow quite well too

 

Alluminum is lighter but it doesn't necessarily make more power...the heads and intake on the LS1 make the biggest difference, because of the heads and intake they have different cams that allow the cars to pull hard to 6000rpm. Problem with LT1's is they don't seem to build power as well above 5500rpm (not saying they can't be modded or have a cam thrown in) but the manifold and heads on the LT1 cars just don't allow them to make the power up top that the LS1's do.

 

Also the stupid Optispark was replaced!!!! Along with a different air intake for colder air and better exhaust

 

is there a different intake manifold i can put on or ju7st have it ported. I want to be able to take slightly modified ls1 without to much trouble.

 

I think if you just had it ported you'd be ok on the manifold end of things. You can make them flow pretty good, definately good enough to take an LS1 there's people around here running mid 12's at 115+ on their ported intakes it's not that difficult...hopefully someone with more LT1 knowledge will give you better suggestions or more specific ones.

 

how much would it cost to have someone reputable port my intake and also are there any "hidden" mods i can do so that not everyone would know unless they were knowledgeable people.

 

Better cam profile, higher ratio rockers coupled with lower lobe lift (see previous), less chance of lifter float, non-siamesed exaust ports (like a Ferd), different bore/stroke setup, better heads, deep skirted block (my 1960s designed Nissan has this), 6 bolt mains, coil on a plug, composite intake, it just goes on and on - basically the whole package is different.

 

Until you get around the 500 HP mark dont bother messing with the intake other than maybe opening up the front for a larger TB. No use raising the runner on an intake when it will be blocked by the heads intake runner.